1. Field of the Invention
The present invention relates to methods, apparatus, and devices associated with an ophthalmic lens system wherein the lenses may communicate with each other utilizing a secondary electronic external device. More particularly, the present invention relates to an ophthalmic lens system that may depend on the secondary electronic external device to reduce power, communication, and processing requirements within the ophthalmic lenses.
2. Discussion of the Related Art
Traditionally, an ophthalmic device, such as a contact lens, an intraocular lens, or a punctal plug included a biocompatible device with a corrective, cosmetic, or therapeutic quality. A contact lens, for example, may provide one or more of vision correcting functionality, cosmetic enhancement, and/or therapeutic effects. Each function may be provided by a physical characteristic of the lens. A design incorporating a refractive quality into a lens may provide a vision corrective function. Pigmentation incorporated into the lens may provide a cosmetic enhancement. An active agent incorporated into a lens may provide a therapeutic functionality. Such physical characteristics may be accomplished without the lens entering into an energized state.
More recently, active components have been included in a contact lens, and the inclusion may involve the incorporation of energizing elements within the ophthalmic device. The relatively complicated components to accomplish this effect may derive improved characteristics by including them in insert devices which are then included with standard or similar materials useful in the fabrication of state of the art ophthalmic lenses.
The ability for a user's ophthalmic lenses to communicate with each other may expand the possible functionalities of an energizable ophthalmic lens system. Wireless communication may allow one lens to recognize the relative position of the opposite lens, which may provide a more accurate determination of where the user may be looking. Wireless communication may also allow the two lenses to interact with each other, for example, to trigger specific, different actions when a user blinks or winks.
Communication between two contact lenses on a user may be difficult for several reasons. Each contact lens has limited area and volume for batteries and electronic components. For example, the volume available for batteries and electronic circuits in a contact lens may be less than 20 mm3, whereas the volume available for all components in a smartphone may be 50,000 mm3. Likewise, contact lens batteries may have 100 μA-Hr of capacity whereas a smartphone may have a capacity of 1400 mA-Hr. Thus, each contact lens may be limited in transmitter output power and receiver sensitivity.
Lower distance may be typically associated with reduced transmitter and receiver power requirements. Although the contact lenses may only be about 70 mm apart when on a user's eyes, there may not be a direct line of sight between the lenses, so direct light-based communication may not be possible without relying on reflections from nearby objects.
Further, in the event a radio frequency (RF) system may be used, the antenna area available in a contact lens, along with the dielectric properties of the eye and body, may make communication inefficient. Complex processing of signals, decision inputs, and data may also be difficult in contact lenses. The aforementioned limits on area, volume, and battery capacity may constrain the size, speed, computational complexity, and current consumption of a processor. For example, while it may be preferred for application enablement to include a powerful microcontroller or central processing unit (CPU) in contact lenses, state-of-the-art technology may not allow such integration.
Some exemplary systems may detect convergence of gaze to trigger a focus change, and without an external electronic device, the two contact lenses must obtain and transmit gaze direction, determine convergence, and signal the need to change focus. This may require communication between the lenses to carry gaze direction and focus change information. Further, this system may require tight timing synchronization between the lenses. In a system tracking gaze direction instead of just convergence, the transmission and computation requirements may be even higher.
The addition of a larger, external electronic device may permit portions of the communication and/or processing burden to be placed in the external electronic device, thereby easing the requirements on the contact lenses. Similar techniques are used in cellular communications, where a user's handset has limited battery power and limited size, and thus limited transmitter and receiver power and antenna gain. In such an example, the much larger available size and current in the cellular base station permits higher gain, power, and computational complexity.
It may be anticipated that some of the solutions for increasing wireless communication between energizable ophthalmic lenses may provide novel aspects for non-energized devices and other biomedical devices. Accordingly, there may be a need in the art for improved wireless communication between lenses, and utilizing a secondary external device may offer a solution to many of the current issues with inter-lens communication.